EP0895345B1 - Method for monitoring a collectorless dc motor and motor for performing such a method - Google Patents

Abstract

A voltage variable voltage (UC) is compared with another variable, which esp. is dependent on a variable to be controlled, e.g. a temp., in order with a specified comparison criterion, to produce a comparison signal (Udiff). The time difference (Td) between the beginning of the comparison signal (Udiff) and the time point of a second specified rotor setting (c.180 deg) following on the first specified rotor setting. Esp. of a second commutating time point, following on the first commutating time point, or a value (Td') near to this time difference, as well as the sense of this time difference, are determined. Based on this time difference (Td,Td') and their plus or minus sign, the switching 'on' and/or switching 'off' of the stator current (i1,i2) are controlled per unit time, according to at least one specified rule.

Description

The invention relates to a method for monitoring a collectorless DC motor, and a motor for performing such Process.

In many cases it is desirable to have a brushless DC motor on it to monitor whether it is rotating at a sufficiently high speed. This applies z. B. in motors that drive a fan. Becomes such an engine blocked, the electronic devices cooled by the fan become, assume high temperatures or even be destroyed.

From GB-A-2 247 999 a speed monitoring for one is known Fan. This circuit uses the pulse-shaped for monitoring Motor current of this fan. This current is in via a measuring resistor a measuring voltage is converted and processed in the circuit. This Measuring voltage always has one line before the current is switched off a peak, and this generates square-wave pulses at the output of one Operational amplifier. These impulses cause every revolution of the Motor discharges a capacitor via a diode provided for this purpose, and then charging the capacitor through a resistor. The pulsed voltage across this capacitor controls a comparator, if their amplitude becomes large enough, which is the case at low speeds is. This then causes an alarm signal to be generated on an LED.

If the motor becomes too slow, the capacitor mentioned will move towards one high voltage is charged so that the output of the comparator goes high and e.g. an LED lights up or another warning signal is triggered, which indicates that the fan is running too slowly or is at a standstill. - Because of its many parts, this circuit is complex and must - because of different form of motor currents - individually adapted to each motor type become. Provided that the motor current is uniform, as with multi-phase Motors is the case, this circuit cannot be used at all.

EP-A2, 0425479 discloses a collectorless DC motor, the speed of which is controlled depending on the temperature so that it is controlled with rising temperature increases or decreases with falling temperature. To do this a capacitor constantly through a temperature dependent resistor (Thermistor) is charged, and this capacitor is at each Discharge commutation change over a comparator. The tension on this capacitor therefore corresponds to a combination of speed and Temperature. This voltage is compared to a constant signal. As The result of the comparison is a sawtooth-shaped voltage, which controls the energy supply to the motor. The same script also shows one another motor variant, the generation of a speed-dependent voltage by means of diodes connected to two phases of a collectorless motor are. This speed-dependent analog voltage is given a predetermined Voltage compared, and if the speed-dependent voltage - as a result a low speed - too low, an alarm signal is generated.

It is therefore an object of the invention to develop a new method for Monitoring a brushless DC motor, and one appropriate motor to provide.

a) Bei der Bestromung eines vorgegebenen Stranges wird die Zeitdauer der Kommutierungsphase etwa ab der Kommutierung zu Beginn dieser Kommutierungsphase bis etwa zur Kommutierung am Ende dieser Kommutierungsphase fortlaufend als digitaler Wert erfasst;

b) diese Zeitdauer wird mit einem vorgegebenen Schwellenwert verglichen;

c) überschreitet diese Zeitdauer den Schwellenwert, so wird, ggf. unter Berücksichtigung zusätzlicher Parameter, ein Alarmsignal gesetzt.

According to the invention, this object is achieved by a method for monitoring a collectorless DC motor, with the following steps:

a) When current is supplied to a given strand, the duration of the commutation phase is continuously recorded as a digital value, for example from commutation at the beginning of this commutation phase to about commutation at the end of this commutation phase;

b) this time period is compared with a predetermined threshold value;

c) If this time period exceeds the threshold value, an alarm signal is set, possibly taking additional parameters into account.

By means of this method it can therefore be recognized in a simple manner whether a Motor is blocked or rotates too slowly, and you can then stop the motor switch off automatically and generate an alarm signal. This procedure is very accurate and works regardless of the shape of the motor current and regardless of the temperature.

a) Bei der Bestromung eines vorgegebenen Stranges wird die Zeitdauer der Kommutierungsphase etwa ab der Kommutierung zu Beginn dieser Kommutierungsphase bis etwa zur Kommutierung am Ende dieser Kommutierungsphase fortlaufend als digitaler Wert erfasst;

b) diese Zeitdauer wird mit einem vorgegebenen Schwellenwert verglichen;

c) überschreitet diese Zeitdauer den Schwellenwert, so wird der Motor stromlos gemacht. Hierdurch wird erreicht, dass der Motor nicht überhitzt werden kann, wenn er stark gebremst oder sogar blockiert wird, da er dann automatisch nach Überschreiten des vorgegebenen Schwellenwerts stromlos gemacht wird.

Another solution to the problem is a method for influencing the speed of a collectorless DC motor, with the following features:

a) When current is supplied to a given strand, the duration of the commutation phase is continuously recorded as a digital value, for example from commutation at the beginning of this commutation phase to about commutation at the end of this commutation phase;

b) this time period is compared with a predetermined threshold value;

c) If this period exceeds the threshold value, the motor is de-energized. This ensures that the motor cannot be overheated if it is heavily braked or even blocked, since it is then automatically de-energized after the predetermined threshold value has been exceeded.

In many cases, an engine is not constantly blocked, so after some Time could start up again. A particularly preferred version of the inventive method to take into account this fact Subject of claim 4.

a) Es ist eine Vorrichtung vorgesehen, welche die Zeitdauer einer Kommutierungsphase etwa ab der Kommutierung zu Beginn dieser Kommutierungsphase bis etwa zur Kommutierung am Ende dieser Kommutierungsphase fortlaufend als digitalen Wert erfasst;

b) es ist eine Vorrichtung zum Vergleich dieser Zeitdauer mit einem vorgegebenen Schwellenwert vorgesehen;

c) es ist eine Vorrichtung vorgesehen, welche ein Alarmsignal erzeugt, wenn diese Zeitdauer den Schwellenwert überschreitet. Ein solcher Motor hat einen sehr einfachen Aufbau bei sicherer Funktion.

The invention also relates to a collectorless DC motor with an arrangement for monitoring its speed to determine whether this speed falls below a lower limit during operation, with the following features:

a) A device is provided which continuously records the duration of a commutation phase as a digital value from about the commutation at the beginning of this commutation phase to about the commutation at the end of this commutation phase;

b) a device is provided for comparing this time period with a predetermined threshold value;

c) a device is provided which generates an alarm signal if this time period exceeds the threshold value. Such a motor has a very simple structure with a safe function.

In a further embodiment of this motor, a motor of this type is used Counter provided for recording the duration of a commutation phase.

This counter is preferably part of a microprocessor or Microcontroller that is used to control the commutation of the motor.

The rotor magnet of the rotor also preferably has a trapezoidal shape Magnetization, because this results in a favorable efficiency and a Result in noise reduction.

Fig. 1

ein Prinzipschaltbild einer bevorzugten Ausführungsform eines erfindungsgemäßen kollektorlosen Gleichstrommotors,

Fig. 2

ein Schaubild, welches den Verlauf der Drehzahl über der Temperatur zeigt, welcher Verlauf bei einem temperaturgeführten Lüfter angestrebt wird,

Fig. 3

eine Darstellung der Statorströme beim Motor nach Fig. 1 und bei maximaler Drehzahl, und mit der bevorzugten Stromabschaltung in einem Abstand D vor Erreichen der Kommutierungszeitpunkte ta bzw. tb,

Fig. 4

eine Variante zu einer Einzelheit der Fig. 1,

Fig. 5

eine Darstellung von Einzelheiten eines beim bevorzugten Ausführungsbeispiel verwendeten Mikroprozessors,

Fig. 6

eine Darstellung von Kurvenverläufen für den Fall, daß der Motor mit einer Drehzahl läuft, die kleiner ist als die gewünschte Drehzahl,

Fig. 7

eine Darstellung analog Fig. 6 und für den Fall, daß der Motor mit der gewünschten Drehzahl ("Soll-Drehzahl") läuft,

Fig. 8

eine Darstellung analog Fig. 6 und 7 für den Fall, daß der Motor zu schnell läuft,

Fig. 9

eine Darstellung analog den Fig. 6 bis 8 für den Fall, daß der Motor mit der zulässigen Minimaldrehzahl läuft,

Fig. 10

eine Darstellung analog Fig. 6 bis 9 für den Fall, daß der Temperatursensor defekt oder seine Anschlußleitung unterbrochen ist,

Fig. 11

eine synoptische Darstellung des Signals U_dif für verschiedene Fälle, wobei jeweils n die aktuelle Drehzahl und n* die gewünschte Drehzahl ist,

Fig. 12

eine Darstellung, welche zeigt, wie abhängig von der Drehstellung des Rotors verschiedene Rechenvorgänge ("Routinen") vom Mikroprozessor abgearbeitet werden, und zwar für den Fall, daß die Drehzahl zu niedrig ist,

Fig. 13

eine Darstellung analog Fig. 12 für den Fall, daß die Drehzahl zu hoch ist,

Fig. 14

eine Darstellung des Schaltbilds eines bevorzugten Ausführungsbeispiels mit verschiedenen vorteilhaften Einzelheiten,

Fig. 15

ein Flußdiagramm von bei der Initialisierung des Mikroprozessors ablaufenden Vorgängen,

Fig. 16

eine Routine zur lmplementierung von Fig. 13,

Fig. 17

eine Routine zur Implementierung von Fig. 12,

Fig. 18

eine Routine, welche sich jeweils an die Routinen der Fig. 16 und 17 anschließt,

Fig. 19

eine Routine zur Berechnung einer Stellgröße PI für die Drehzahlregelung, oder für die Steuerung der Motordrehzahl,

Fig. 20

eine Rounine zur Berechnung eines Alarmsignals,

Fig. 21

Schaubilder zur Erläuterung der Flußdiagramme nach den Fig. 15 bis 19,

Fig. 22

ein Flußdiagramm analog Fig. 16, aber mit eingezeichneten NOP-Befehlen,

Fig. 23

ein Flußdiagramm analog Fig. 17, aber mit eingezeichneten NOP-Befehlen,

Fig. 24

ein Diagramm analog Fig. 12 zur Veranschaulichung der Vorgänge, die bei aufeinanderfolgenden Kommutierungsphasen ablaufen, und

Fig. 25

ein Schaltbild analog Fig. 1 für den Fall, daß der Motor nur mit seiner maximalen Drehzahl betrieben werden soll, also ohne Drehzahlregelung, wobei aber die Alarmfunktion, die Blockiersicherung, und das leistungslose Ein- und Ausschalten ebenso wie bei Fig. 1 arbeiten, d.h. der Programmablauf bleibt für diesen Fall gegenüber Fig. 1 unverändert.

Further details and advantageous developments of the invention result from the exemplary embodiments described below and shown in the drawing, which are in no way to be understood as a restriction of the invention, and from the remaining subclaims.
It shows :

Fig. 1

2 shows a basic circuit diagram of a preferred embodiment of a collectorless DC motor according to the invention,

Fig. 2

a diagram which shows the course of the rotational speed over the temperature, which course is sought for a temperature-controlled fan,

Fig. 3

2 shows a representation of the stator currents in the motor according to FIG. 1 and at maximum speed, and with the preferred current cut-off at a distance D before the commutation times ta or tb are reached,

Fig. 4

a variant of a detail of Fig. 1,

Fig. 5

2 shows a representation of details of a microprocessor used in the preferred exemplary embodiment,

Fig. 6

a representation of curves in the event that the engine is running at a speed that is less than the desired speed,

Fig. 7

a representation analogous to FIG. 6 and in the event that the motor runs at the desired speed ("target speed"),

Fig. 8

6 and 7 for the case that the engine is running too fast,

Fig. 9

6 to 8 for the case that the motor is running at the permissible minimum speed,

Fig. 10

6 to 9 in the event that the temperature sensor is defective or its connecting line is interrupted,

Fig. 11

a synoptic representation of the signal U _dif for different cases, where n is the current speed and n * is the desired speed,

Fig. 12

a representation which shows how, depending on the rotational position of the rotor, various computing processes (“routines”) are processed by the microprocessor, specifically in the event that the rotational speed is too low,

Fig. 13

a representation analogous to FIG. 12 in the event that the speed is too high,

Fig. 14

1 shows the circuit diagram of a preferred exemplary embodiment with various advantageous details,

Fig. 15

1 shows a flowchart of processes which take place during the initialization of the microprocessor,

Fig. 16

13 is a routine for implementing FIG. 13;

Fig. 17

a routine for implementing FIG. 12,

Fig. 18

a routine which follows the routines of FIGS. 16 and 17,

Fig. 19

a routine for calculating a manipulated variable PI for speed control or for controlling the engine speed,

Fig. 20

a rune to calculate an alarm signal,

Fig. 21

15 to 19 are diagrams for explaining the flowcharts,

Fig. 22

16 shows a flowchart analogous to FIG. 16, but with NOP instructions drawn in,

Fig. 23

17 shows a flowchart analogous to FIG. 17, but with NOP instructions shown,

Fig. 24

a diagram analogous to FIG. 12 to illustrate the processes that take place in successive commutation phases, and

Fig. 25

a circuit diagram analogous to Fig. 1 for the case that the motor should only be operated at its maximum speed, that is without speed control, but the alarm function, the anti-lock device, and the powerless on and off as in Fig. 1 work, ie the program flow remains unchanged in this case compared to FIG. 1.

Fig. 1 shows the basic principle of the invention in a highly abstracted representation. 20 denotes a microprocessor to which a ROM 21 is assigned, in which commands necessary for the operation of an engine 25 are stored. These commands, or the operations they control, are as follows are explained using flow diagrams.

Fig. 5 shows the connections of a microprocessor of the type 17103GS, as in of the present invention can be used. This microprocessor 20th contains a ROM with a memory capacity of 512 words of 16 bits each. Therefore this ROM is not shown separately. The connections and the Reference numerals for this microprocessor can be found directly in FIG. 5 and are therefore not additionally described. These reference numerals according to FIG. 5 are also used in FIG. 1, so that FIG. 5 is referred to for their explanation can be. This also applies to the designation of the individual ports. The reference numbers refer to the type 17103GS, a common one Microprocessor with four bit data width.

The arrangement according to FIG. 1 serves to control or regulate a motor 25 in a temperature-dependent manner in such a way that this motor runs at a low speed n at low temperatures, but at a high speed at high temperatures. A known application of such a motor is the drive of a device fan. Fig. 2 shows a preferred course of the speed over temperature; this course does not require any additional explanation. The engine speed n is limited down to a value n _min , z. B. to the value n _min , and up to the value n _max , ie it can be between 1400 and 2800 rpm, for example, if it is a device fan.

Above 50 ° C, the maximum speed is usually required, however is the highest possible speed of the engine 25, which is usually is not regulated, but could also be regulated within the scope of the invention. Naturally, the arrangement according to FIG. 1 can also be used to regulate a constant Speed can be used. For this purpose, only the NTC resistor 26 has to go through a constant resistance can be replaced.

If the speed of the motor 25 falls well below the lower limit, e.g. B. by a bearing damage to the engine, it is desired that the arrangement emits an alarm signal so that no damage can be caused by overheating when the motor drives a fan and consequently this fan promotes too little air. It is also desirable that such a motor automatically runs at the speed n _max in the event of damage to its temperature sensor 26, which is designed here as an NTC resistor. This applies e.g. B. when the line connection to the temperature sensor 26 is interrupted, which in the arrangement shown per se means a signal for a very low speed, which should correspond to the speed n _min according to the logic of the control arrangement used. In the present invention, this signal corresponds to the speed n _max . Furthermore, it is often desired that the motor current be interrupted when the motor is blocked, which is also referred to as an "anti-lock device".
The motor 25 preferably has a permanent magnetic rotor 27 which controls a rotor position sensor 28, e.g. B. a Hall IC.
This is shown twice in Fig. 1 to facilitate understanding. Its output signal KOMM is fed to the corresponding input (port) 7 of the microprocessor 20. This signal KOMM controls the commutation of the currents i ₁ and i ₂ in two stator winding phases 31 and 32 of the motor 25.

6 and 7 show, for example, a low rotor position signal (KOMM = L) means that only strand 31 can be switched on (current i ₁ ), and a high rotor position signal (KOMM = H) means that only the strand 32 can be switched on (current i ₂ ). The duty cycle of these currents i ₁ and i ₂ depends on the temperature at the temperature sensor 26 and on the load on the motor 25, as will be described below.

As shown, two npn power transistors 33, 34 are used to control the currents i ₁ and i _2. Their bases are each connected via a resistor 35 and 36 to the outputs (port) 9 and 10 of the microprocessor 20, respectively emit the driver signals out1 or out2 during operation. Furthermore, a capacitor 37 and 38 is connected between the collector and base of the transistors 33, 34, which together with the relevant resistor 35 and 36 serves as a delay element when the relevant transistor 33 or 34 is switched off.

For this purpose, reference is made to FIG. 3, which shows the currents i ₁ and i ₂ at full load, that is to say at maximum speed.

In Fig. 3, the commutation times are designated t _a and t _b . If the current i _{1 is} only switched off shortly before the commutation time t _a and no capacitor 37 is used, a switch-off current peak 40 results and the motor generates strong noises.

If, on the other hand, the current i _{1 is} switched off at a point in time, which is the exaggerated time span D before the commutation point in time t _a , and the RC combination 35, 37 is used, the current curve 42 shown in broken lines and the motor result 25 runs much quieter. The same applies - because of the symmetry of the circuit - for the current i ₂ . According to the invention, both measures are combined in a preferred manner in order to achieve quiet running of the motor 25.

The distance D can be changed in the same way by the controller as a function of the speed, as described in detail below for the value PI (for example FIG. 21 d). For this purpose, half of the calculated value PI can be used for the delay before the power is switched on, and the other half for the premature switch-off, as a variable value D. This optimizes the motor and reduces its running noise even more, and is therefore particularly suitable for motors with a rather sinusoidal magnetization of the rotor 27. The rotor 27 preferably has a trapezoidal magnetization with narrow gaps between the magnetic poles in order to obtain a corresponding trapezoidal counter-emf. (The back emf is also called the induced voltage.) This measure improves the efficiency and also leads to a reduction in noise. The currents i ₁ , i ₂ according to FIG. 3 are measured in a motor with such a magnetization of the rotor 27. (Such a trapezoidal magnetization with narrow pole gaps is sometimes referred to in the jargon of electrical engineering as "rectangular magnetization".)

To explain a preferred engine design for the construction shown with two strands 31, 32 e.g. referred to DE 23 46 380 C2 be, or on engines with a flat air gap according to DE 22 25 442 C3. It are two-pulse motors as defined in asr-digest for applied drive technology, 1977, pages 27 to 31. These motors can be used in Within the scope of the invention also be single-stranded, in which case Control of the single line requires a bridge circuit, cf. the mentioned reference asr.

In the same way, the invention can also be used for brushless motors of others Use types, e.g. for three-strand, three-pulse engines, by only one To give an example. The arrangement shown with a two-pulse, two-strand However, the engine is particularly simple and advantageous since it is a minimum components required. This is especially true for fans or analog applications, e.g. Scanners in laser printers.

An npn transistor 44 is connected to the alarm output 9 of the microprocessor 20 connected to the collector e.g. a bell or a warning lamp can be connected to an audible or a visual alarm signal deliver when the speed n (Fig. 3) is too low. Often this signal is also processed internally by a user, e.g. in the device in question.

As shown in Fig. 2, in a temperature range between Ta (e.g. 20 ° C) and Tb (e.g. 50 ° C) the speed increases with increasing temperature, i.e. on certain temperature value T * should have a certain speed in this area n * effect. The temperature T * thus acts like a speed setpoint for the Speed n *, and this is therefore a speed control.

For this, a difference must be made between the desired one Speed n *, which is also called the target speed, and the actual Speed, which is also called the actual speed. Referred to this difference one also called control deviation.

With a digital speed controller, the control deviation is usually calculated digitally, which is expensive and takes a relatively long time. In the present invention the control deviation is preferably calculated analogously, and this allows calculation steps for the Let the control process run and thereby accelerate it considerably. In addition, the invention allows a microprocessor with less Data width to use, since the digital computing processes no counter with require large computing capacity. This is an important advantage of the present one Invention.

The arrangement shown in Fig. 1 has a positive line 45 and a negative line 46, between which e.g. a voltage of e.g. 24 V is present which motor 25 is directly connected as shown. About a resistance 48 and a zener diode 49 becomes a regulated voltage on a line 50 from e.g. + 5 V generated. To this is a series resistor 52 and one Junction 53 of NTC resistor 26 connected to its other Connection on line 46, that is to ground, is. How to easily recognizes, the potential of node 53 becomes higher as the temperature decreases because then the resistance of resistor 26 increases. Also the microprocessor 20 and a comparator 57 described below connected to this regulated voltage, but this is not shown to not to overload the drawing.

Breaks the lead to NTC resistor 26 at location 54 or at the location 55, this has the same effect as a sharp decrease in temperature, i.e. the potential at node 53 then jumps to the value of the potential of Line 50, so to a high value.

The node 53 is connected to the minus input of a comparator 57, the output 58 of which is connected to the port 6 of the microprocessor 20, which is labeled DIF in FIG. 5. This is because a voltage U _dif occurs at the output 58 of the comparator 57, which is explained below and with the aid of which the control deviation (as defined above) can be easily detected.

To the line 50 is also via a charging resistor 62 and a node 63 a capacitor C is connected. The node 63 is with the Plus input of the comparator 57 connected, also to the port 13 of the Microprocessor 20. An npn transistor is internal to this port 13 in microprocessor 20 65 connected by means of the commands of the microprocessor 20 can be controlled.

Operation of Fig. 1st

As previously explained, transistor 65 discharges capacitor C when it is Transistor is controlled by an appropriate command. At a The port 13 of the microprocessor 20 receives such a discharge — in FIG. 5 DISCHARGE denotes - a low potential, i.e. DISCHARGE = L. Should be the other way round the capacitor C are charged, the port 13 is at a high potential placed, so ENTLAD = H. With ENTLAD = L the capacitor C, which is called Storage element is used, set to an initial value, namely one almost completely discharged state. This happens at a given first rotational position of the rotor 27, and this is measured (in the exemplary embodiment), via the output signal KOMM of the rotor position sensor 27. It takes not to be explained at this point that rotor positions on many Can measure species, e.g. even without a sensor directly from the voltages and / or Currents in strands 31, 32. The KOMM signal of a Hall IC enables but a technically simple solution, and its use is therefore preferred because it is in the area of the commutation positions of the rotor abruptly changes from a high value (H) to a low value (L), or the other way around. How often this happens with a rotor revolution depends on the Number of rotor poles. With a two-pole rotor 27, as shown in FIG. 1 very much is shown schematically, this happens twice per rotor revolution, and these places of great change are 180 ° apart. These are the Commutation points of the motor. A four-pole rotor would have four such places per revolution, with a six-pole rotor six places, etc. A low number of poles has the advantage in the context of the invention that the microprocessor 20 more computing time is available, or that a slower Microprocessor can be used.

It should be noted that in the exemplary embodiment, the signal DISCHARGE is only set to H a short time after commutation, cf. FIG. 21. This time also corresponds to a specific rotor position.

In the exemplary embodiment, the arrangement is chosen so that the charge of the Capacitor C can only be started after the signal COMM has gone from H to L. Fig. 6 shows this in the event that the speed of the Motor is lower than the desired speed n * (Fig. 2), which is the current Temperature T * at sensor 26 corresponds and consequently the setpoint n * represents for the engine speed.

This change in the signal KOMM from H to L sets the DISCHARGE signal at port 13 to H at time t ₁₀ in FIG. 6, and the capacitor C is charged via the resistor 62, in this case after an e-function. (Naturally, a linear charge would also be possible). As a result, the voltage U _c at the capacitor C rises, as shown in FIG. 6 _c , and at the time t ₁₁ the potential of the point 63 reaches the level of the potential at the point 53, the latter corresponding to the instantaneous temperature T * at the sensor 26 and consequently represents the setpoint n * for the engine speed.

If the potentials of the points 53 and 63 are the same, the output 58 of the comparator 57 is switched from L to H, and the voltage U _dif , which is shown in FIG. 6b, is thus obtained there.

The signal U _dif = H preferably causes ENTLAD = L to be set immediately afterwards in the program sequence, cf. Fig. 21, that is, the capacitor C is then immediately discharged again, whereby U _{dif takes} the form of a needle pulse. This immediate discharge results in particularly quiet engine running.

However, the voltage U _dif can also be kept at H up to the next commutation point. In this case, when U _dif = H and KOMM changes from L to H or from H to L, ENTLAD = L is set and the capacitor C is discharged again via the transistor 65 (in the microprocessor 20). This occurs in this case at time t ₁₂ in FIG. 6. The following description relates to the preferred variant with immediate discharge of the capacitor C after the signal U _{dif has occurred} . This is the case with this variant - cf. the following flow diagrams - temporarily stored in the form of a signal U _difalt = H, so that the information from the signal U _{dif is} not lost after the capacitor C has been discharged.

The control deviation is now measured as follows:
From the commutation point t ₁₀ , at which the charging of the capacitor C was started, one goes to the next commutation point t ₁₂ , and one measures the time difference T _d from this (next) commutation point t ₁₂ (or a point in its vicinity) to Start of U _dif , _i.e. until time t ₁₁ . Since t _{11 is} earlier than t ₁₂ if the speed is too low, this time T _{d is} measured as negative. A negative T _d means that the speed is too low, the amount (absolute value) of T _d indicating how much the speed is too low. Accordingly, the currents i ₁ (FIG. 6d) and i ₂ (FIG. 6e) through the winding strands 31 and 32 are made larger in this case in order to increase the speed.

FIG. 12 shows how this happens in principle. FIG. 12a shows the signal KOMM, here for approximately a rotor rotation of 360 ° in the case of a two-pole motor 27. FIG. 12b shows the signal U _dif just described in the event that the speed is too slow, ie the control deviation is - T _d .

As indicated at 70 in Fig. 12, during the first degrees the full Revolution calculates a value PI, whereby PI for proportional-integral control stands. This is done from a numerical value P for the proportional control, and a numerical value I for the integral control, e.g. according to the formula PI = I + 2P, where the factors I and P from previous revolutions of the engine are present are and are stored in corresponding memories. (When switching of the motor are corresponding values for I and P during initialization specified.)

This value PI then determines, as shown, by how many degrees after the end of the calculation phase the current i ₁ (through the strand 31) is switched on, as indicated at 72 in FIG. 12. So the larger PI becomes, the smaller this current becomes. The start of the current flow is denoted by t ₁ . This timing is achieved in that the output signal out1 at the output 9 of the microprocessor 20 is made high when the current i _{1 is to be} switched on.

This current then flows e.g. during a rotation angle of 110 ° and it will switched off before reaching the commutation position, which is the angle here Corresponds to 180 °, namely by an angle D in front of this commutation position, where the value D is a few degrees. This is used when switching off the Avoid stator current peaks.

The time measurement for the control deviation -T _d begins with the start of the signal U _{dif ,} and this measurement lasts until the commutation position, that is to say up to 180 °.

Since the motor runs too slowly, the values for P and I are reduced during this period T _d , and the more the longer T _d , the more so. This is indicated at 74 in FIG. (If the controller were only a P controller, of course only one value for P would be changed.) How this is done is described in detail below with reference to FIG. 17.

At the rotary position 180 °, ie at the end of the measurement of T _d , there are already modernized values for P and I which are smaller than before and in the angle of rotation range of z. B. 180 ° to 190 °, a new value PI * is now calculated from these modernized values, as indicated at 76 in FIG. This calculation is described in detail below in FIG. 19. This value PI * then, as indicated at 78, determines the switch-on time t ₂ for the current i ₂ in the branch 32, and this current i ₂ therefore flows longer, for example. B. during 120 °, as the current i ₁ . The current i _{2 also} ends by the value D before the next commutation position, which is 360 °. Since the current i _{2 flows} during a longer angle of rotation, a longer driving torque is generated on the rotor 27 and the motor becomes faster, ie the speed n approaches the value n *.

In the angular range of e.g. 360 ° to 370 ° (corresponding to 0 ° to 10 °) could the value PI is calculated again from the stored values for P and I, that have not changed. Here, however, in an advantageous further development Alarm monitoring also take place according to the invention, i.e. a special computer program determines whether the speed n is below a lower limit lies and gives an alarm if this is the case. This is indicated at 80 in FIG and is described in detail below in FIG. 20.

Following this, the value PI * calculated at 76 is used further and determines the point in time t ₃ at which the current i _{1 is} switched on. This is explained at 82 in FIG. 12.

The processes are then repeated, ie a signal U _{dif is} generated again, which occurs later in this case because the speed has increased somewhat, so that the absolute value of -T _d becomes shorter; the values for P and I are changed, ie reduced further, a new value PI is calculated, etc., as already described in detail.

In this way, different sections of a rotor revolution are different Assigned calculation steps, i.e. determines the position of the rotor 27 about what the microprocessor 20 is currently computing or measuring. Different said, the rotor position controls the current program flow.

Fig. 7 shows what happens when the motor 25 at the desired speed running, i.e. the engine speed n is equal to the desired speed n *.

Here, too, the charging of the capacitor C is started after the signal KOMM changes from H to L, for example in FIG. 7c at the time t ₁₄ . The voltage U _C then rises and reaches the voltage U ₅₃ at the node 53 very shortly after the point in time t ₁₅ at which KOMM changes from L to H. From this point in time t ₁₅ , the time T _d is now measured, and since the rising edge of U _dif practically coincides with t ₁₅ , T _d = 0, ie there is no control deviation.

In this case the values for P and I are correct and are therefore not changed, i.e. the distance PI, e.g. 12 at 72 in FIG. 12 also remains the subsequent current pulses unchanged.

In operation, the engine runs largely in this state, ie the values for P and I change only slightly when the engine 25 is running and the temperature at the sensor 26 does not change. Depending on the temperature, relatively short motor current pulses i ₁ and i _{2 result} , as shown in FIGS. 7d and 7e.

Fig. 8 shows what happens when the speed n becomes higher than the desired one Speed n *. This can e.g. be the case when suddenly cold air is sucked in (a window is opened in winter) and thereby the resistance value of the Sensor 26 increases rapidly.

Here, too, the charging of the capacitor C is started at a time t ₁₇ , at which the signal KOMM goes from H to L, and the measurement of T _d takes place approximately from the time t ₁₈ , at which the KOMM then immediately again from L to H goes.

The signal U _dif only occurs here at a time t ₁₉ which is later _than t ₁₈ , ie T _d is positive here. The positive sign means that the engine is running too fast, and the absolute value of T _d indicates how much the engine is running too fast. Accordingly, the motor currents i ₁ and i ₂ must be made shorter here. Fig. 13 shows how this happens.

Like FIG. 12, FIG. 13 shows the processes with a full rotor rotation of 360 °, as indicated in FIG. 13a. The angular position starts at 180 ° on the left. In the middle it reaches 360 ° = 0 °, and on the right again 180 °, ie the rotation is completed there.

In Fig. 12 the speed was too low and therefore T _{d had} to be measured in the period from 0 ° to 180 ° in which Komm = L.

In Fig. 13 the speed is too high and therefore T _d must be measured in the period from 180 ° to 360 ° in which Komm = H.

13, too, at the beginning, i.e. in the angular range directly after 180 °, during a rotation of e.g. 10 ° the PI value from the existing values calculated for P and I, as explained in the description of FIG. 12. This is explained in FIG. 13 at 85 and takes place with the routine according to FIG. 19.

This value PI then determines the starting point t _{1 of} the current i ₂ , as indicated at 87 in FIG. 13.

Simultaneously with this calculation of t ₁ , a value T _d 'is also measured here, which is somewhat shorter than T _d , because the measurement does not begin until the calculation phase 85 has ended, as can be clearly seen from FIG. 13. This can be compensated for in a program if necessary, since the duration of the calculation phase 85 is known, but the arrangement also functions very satisfactorily if the value T _d 'is measured.

Since the motor is running too fast, the values for P and I are too small, and therefore the longer T _d 'lasts, the more they will increase during the period of T _d '. At the end of T _d ', new, increased values for P and I are obtained which are suitable for reducing the speed somewhat.

This is explained in FIG. 13 at 89 and occurs with the one shown in FIG. 16 Routine.

It is the place to point out that in FIG. 12 the measurement of a negative T _d (step 74) is separated in time from the calculation of the time point t ₁ (step 72), while in FIG. 13 steps 87 and 89 are separated in time must run in parallel. Different control algorithms are required here. Since, by definition, the charging of the capacitor C is started when the signal KOMM changes from H to L, that is to say in FIGS. 12 and 13 with the commutation position 360 ° = 0 °, the algorithm for "speed too low" preferably runs in the Rotation angle range in which KOMM = L, and the algorithm for "speed too high" preferably runs in the rotation angle range in which KOMM = H, as shown in FIGS. 12 and 13.

Would the charging of the capacitor C be started when KOMM from L to H goes, so at the commutation position at 180 °, the algorithm for "Speed too low" then run when KOMM = H, and the algorithm for "speed too high" should then run if COMM = L. This results in derive from the symmetry of an electric motor. This - not shown - Variant can have advantages in some cases.

a) die Kommutierung steuern, und

b) die Messung der Regelabweichung ermöglichen.

In the same way, the measurement of T _{d can} also take place at other points in the rotor revolution, ie if, for example, the Hall generator 28 is located at a different position of the rotor relative to the rotor 27, this does not play a role in the measurement of the time T _d and its sign , It is only important that suitable signals for controlling the charge of the capacitor C (ie for the start of the charge and for the discharge) or for a measurement T _d are present at defined points in the rotor rotation. The currents i ₁ and i ₂ may naturally only flow in certain rotation angle ranges of the rotor, namely in the rotation angle ranges in which the already mentioned back emf is high, and when the Hall IC 28 is adjusted so that these currents are in the correct ones Angle range flow, its output signal KOMM can perform both functions, namely

a) control commutation, and

b) enable the measurement of the control deviation.

Back to Fig. 13. In the area immediately after 360 = 0 °, e.g. from 0 ° to 10 °, a new PI * is calculated from the previously modernized values of P and I, which is larger than the previous PI here, and this is at 92 in FIG. 13 explained. The routine of FIG. 19 is used for this.

The current starting point t ₂ is then calculated at 94 on the basis of the new value PI *. For example, while the current i ₂ flowed during a rotation angle of 130 °, the current i _{1 flows} only during a rotation angle of 120 °. (In practice, the differences are naturally much smaller, but the use of larger differences enables a clearer graphic representation.)

For the reasons explained, both current i ₂ and current i ₁ are switched off by the distance D before the commutation position (360 ° or 180 °), which is taken into account in program step S131 (FIG. 15).

Following the commutation position 180 ° (on the right in FIG. 13), it can be calculated at 96 whether an alarm must be given or the value PI can be calculated again. This remains unchanged since there is no new measured value T _d , as explained at 98 in FIG. 13.

It is therefore essential that the measurement of T _{d takes place in} parallel with the modemization of the values for P and I, and possibly also in parallel with the calculation of the current starting point, and that one measurement is then used for several current pulses until one new measurement takes place. In the course of one or two rotor revolutions there are no major changes in speed.

Fig. 9 shows what happens at very low temperatures. In this case the potential U ₅₃ becomes very high and the voltage U _c only reaches this potential after a few engine revolutions, ie T _d has a positive value and is very large. This would correspond to a very low engine speed n, which is not permitted. In this case, the controller switches to proportional control and maintains a lower speed of 1400 rpm, for example. The current pulses i ₁ and i ₂ are extremely short in this case.

10 shows what happens when the temperature sensor 26 is defective, for example because of an interruption at points 54 and 55. In this case, the potential U ₅₃ becomes so high that the voltage U _C never reaches this potential U ₅₃ . In this case, the arrangement switches to the maximum speed, as symbolically shown in FIGS. 10d and 10e, ie the stator current pulses i ₁ , i ₂ are given their maximum possible length.

11 shows the different possible cases synoptically:
In Fig. _11b the motor is much too slow and therefore T _{d is} negative and has a large absolute value.

In Fig. 11 c the motor is a little too slow. T _d is negative, but its absolute value is smaller compared to Fig. 11b.

In Fig. 11d the motor is running at the correct speed n = n *. The voltage U _dif is now in the range of the signal KOMM = H. T _d has the value 0.

Fig. 11e shows the situation when the engine is running a little too fast. T _d is positive here and has a relatively small value.

In Fig. 11f the motor is much too fast and T _d is positive and has a large absolute value.

11 g the sensor is defective. T _d has a very high value or the value infinite, ie U _dif constantly keeps the value 0. The evaluation of this state by the microprocessor 20 causes the motor 25 to switch to the maximum speed.

In practice, the circuit with the comparator 57 (Fig. 1) by means of a npn transistor 100 and a pnp transistor 102 can be realized, as in FIG. 4 shown. The same parts as in Fig. 1 are in Fig. 4 with the same reference numerals are referred to and are therefore not described again.

The base of transistor 100 is connected to node 63, its emitter is connected to node 53, and its collector is connected to the base of transistor 102. The emitter of transistor 102 is connected to a positive voltage via a resistor 103 and its collector is connected a resistor 104 connected to ground 46. The voltage U _dif can then be _tapped off at the resistor 104 during operation.

14 shows a circuit with further details. Used for the comparator the circuit according to FIG. 4, otherwise the circuit according to FIG. 1, which is why the same reference numerals are used for the same parts as in the 1 and 4, and these parts are usually not described again.

In the supply line from the positive line 45 (e.g. 24 or 48 V operating voltage) to the electronic components is a diode 108, which is included wrong connection, also called "wrong polarity", blocks, and destruction the electronics prevented. There are one for the power supply of the Hall IC 27 Zener diode 109 and a ballast resistor 110 are provided.

A clock 112 from is connected to the connections 1 and 2 of the microprocessor 20 e.g. 6 MHz connected. Between port 7 and line 50 is a Resistor 114. This is the so-called pull-up resistance of Hall IC 27.

The reset connection (port 3) of the microprocessor 20 is with a node 114 connected. The latter is through a resistor 115 to the positive lead 50 and connected to the negative line 46 via a capacitor 116.

When the motor is switched on, the capacitor 116 is discharged and consequently has node 114 first has the potential 0 V, i.e. a low signal L. This signal L causes the initialization of the microprocessor 20, such as it is described below at step S130. Then the Capacitor 116 on, and the signal on port 3 goes high, causing the initialization is completed.

The potentials at ports 14 and 15 determine the minimum speed of the motor, that is to say the value n _min in FIG. 2. This is achieved by the resistors 118, 119 and the connections shown to the positive line 50 and to the negative line 46, respectively.

Port 4 is connected to negative line 46. The potential at port 12 (H or L) determines the duration of the AVZ alarm delay (0 or 10 seconds). In the exemplary embodiment, ports 5 and 12 are connected to line 50 (+). The I / O port enables digital control of the motor 25: if it is placed on L, the engine stops. If it is placed on H - as in Fig. 14 - it runs like this the motor. This enables the motor to be switched on using a low-voltage signal.

In series with the motor 25 there is a PTC resistor 121 on the plus side Fuse when the motor locks up, and on the negative side a low-resistance resistor 122, which is favorable for the switching operations. A zener diode 123 is connected in parallel with the capacitor 37, in parallel with the capacitor 38 a zener diode 124 to protect the microprocessor 20 from overvoltages to protect from the motor windings 31, 32.

The method of operation has already been described with reference to FIGS. 1 and 4, and the Initialization when switched on by means of resistor 115 and the capacitor 116 has also already been explained. Compare to the microprocessor 20 also Fig. 5, which shows the symbolic designation of the individual Specifies ports.

Below are the flowcharts for the operations shown in the explained in detail how they are shown in FIGS. 15 to 20 and how they in Present the optimal level of knowledge at the moment. (Programs are subject frequent changes and optimizations, as is known to the expert.)

FIG. 15 shows in step S130 the processes when the motor is switched on, that is to say the power-ON reset, which is triggered when the motor 115 is switched on by the resistor 115 and the capacitor 116, as described in FIG. 14. The various ports of the microprocessor 20 are queried here, that is to say in FIG. 5 the port ATS (whether H or L) which indicates the alarm speed, for example 1200 rpm, and also the port SEN which indicates whether an alarm signal is to be deleted again may, if the speed becomes normal again, or if the alarm signal must be saved. Ports NG0 and NG1, which together define the minimum speed n _min , for example 1400 rpm, are also queried, and the already explained value I / O is queried, which indicates whether the engine should be running or stopped. The values NG0 and NG1 are then decoded and result in a value KZ _min for the minimum speed, for example 120 units. (The larger this value, the lower the speed).

SENSAB auf L.

PI auf einen niedrigen Wert, z.B. 0.

KZ_alt auf einen hohen Wert, z.B. 255.

I auf einen niedrigen Wert, z.B. auf 0.

PZ auf den Maximalwert, hier z.B. 15.

U_difalt auf H.

The following registers are also set:

SENSAB on L.

PI to a low value, e.g. 0.

Concentration camp _old to a high value, e.g. 255.

I to a low value, e.g. to 0.

PZ to the maximum value, here e.g. 15.

U _difalt on H.

SENSAB = L means that there is no interrupted sensor connection 1, that is, there is no interruption in the lines to sensor 26 in FIG. 1 is at position 54 or 55. SENSAB = H means maximum speed and overrides the regulation, i.e. PI = 0 is set here, cf. Fig. 19, Step S165.

PI is the manipulated variable of the controller. As FIG. 21d shows, it determines when the motor current is switched on: the current i ₁ (or i ₂ ) is only switched on when the commutation counter KZ has reached the counter reading PI, that is to say the manipulated variable. If PI is large, the current is switched on late, i.e. little power. If PI is small, the power is turned on early, so a lot of power.

KZ _alt is a count value for the commutation counter KZ. (The commutation counter KZ is part of the microprocessor 20 - FIG. 5 - and therefore not shown separately.) As can be seen from FIG. 21d, the commutation counter KZ begins to count shortly after commutation when the calculation phase 128 (explanation in FIG. 12 at 70 or 80) is complete. When the commutation counter has counted up to PI, it switches on the relevant line and a motor current flows. If the commutation counter has reached the value KZ ' _old , which is smaller by the value D (eg 4 units) than KZ _old , it switches this current off again.

The commutation counter KZ then continues to count until the next commutation and thereby measures the value KZ, that is the time period from KZ = 0 (end of the calculation phase 128) to the next commutation (t ₃₀ in FIG. 21 a). If it becomes too high, this value serves as an indication of a blockage of the rotor, as explained below. This value KZ is then stored as the most probable value for the duration of the next commutation phase in the register KZ _old as the value KZ _old . It can also be advantageous to use the moving average of a plurality of values for KZ measured just a short time ago for the value KZ _old , since then the engine runs even more smoothly.

This variant is not shown in the flow chart; for the specialist their implementation is not a problem.

In step S130, KZ _{old is} specified since there is still no value from a measurement.
I is the integral factor of the speed controller, which must be specified when starting.
PZ is the counter reading of a test counter, cf. Fig. 18.
PZ = 15 ensures that a new value for PI is calculated immediately after the first measurement and that an alarm is only calculated later. A start delay AVZ means that, for example, no ALARM signal can be triggered 10 seconds after the start, cf. Fig. 20.

U _difalt is a register value that is set to H if the value U _dif = H occurs during KOMM = L. With KOMM = H, this blocks the change in the values for I and P, but not with KOMM = L. This value is set to H at start because the speed is too low at start, so that P and I with KOMM = L must be changed, namely reduced.

The microprocessor 20 then goes to step S131, which is run through with each commutation change. Here, from the already explained value KZ _old (FIG. 21d), which results with each commutation (as the distance between KZ = 0 and t ₃₀ , or as the already explained moving average, which is recalculated with each commutation), the value D subtracted, for example 4 units, so that the value KZ ' _old results. This is set as a limit in the commutation counter KZ so that the current is switched off when this value is reached. In addition, the commutation counter KZ is reset to zero in step S131 so that it counts again from the beginning, that is to say from KZ = 0, as shown in FIG. 21d, and the proportional factor P of the controller is set to P = 0.

At step S132, it is checked whether the enable signal I / O is high. Only in in this case the motor can start. Otherwise the program goes to step S131 back. This allows the engine to be viewed from a computer Taxes.

It is then checked in step S201 whether the signal KOMM is high or low. If COMM = H, the program checks in step S202 whether the signal U _difalt = H. If yes, a sign signal REG is set to -1 in step S203, and the program then proceeds to the routine of FIG. 16. REG = -1 means that the speed is too low, and consequently in the routine of FIG. 16 a change in parameters I and P is blocked.

If U _difalt = L, REG = + 1 is set in step S204, and the program also proceeds to the routine according to FIG. 16. REG = +1 means that the speed is too high, and consequently follows in the routine 16 the parameters for I and P may be increased in accordance with the measured value for T _d .

If the signal KOMM = L in step S201, the program goes to step S205. There it is checked whether U _difalt = H. If yes, REG = +1 (speed too high) is set in step S206, and the program proceeds to the routine of FIG. 17. In this case, the change of the parameters for I and P is blocked there.

If the answer is no in step S205, the program goes to step S207, where REG = -1 is set, ie the speed is too low, and the program goes to the routine of FIG. 17, where the parameters for I and P may be reduced in accordance with the measured value for T _d .

As a preliminary remark to FIGS. 16 and 17, it should be said that those shown there Loops also cause a time measurement, namely by changing the Commutation counter KZ (in steps S143 and S154). This requires, that each loop run, regardless of which way, lasts the same length, and This is achieved in that certain loop runs, which are in themselves shorter are filled with NOP commands, which only consume time, but nothing cause. These NOP instructions are not shown in a flow chart, however, this is pointed out because an optimal function presupposes that everyone Loop pass is as long as possible. The duration of a loop pass 16 thus corresponds to the duration of a loop run of FIG. 17, see above that the values for concentration camps are directly comparable. 22 and 23 show this NOP instructions.

Fig. 16 shows the routine for KOMM = H. This routine implements Fig. 13, if the engine is too fast, i.e. the factors P and I are only changed here, namely enlarged if the engine is too fast.

In step S133 it is checked whether the commutation counter KZ (in the microprocessor 20) has reached the value PI, cf. Figure 21d. If this is the case, the current i _{2 is} switched on. In step S134 it is checked whether the commutation counter has reached the value KZ ' _old , and then the current i ₂ is switched off again.
out2 = L means that the current i _{2 is} switched off.
out2 = H means that the current i _{2 is} switched on.
The same applies to out1.

Step S135 thus means that both currents i ₁ and i _{2 are} switched off, and S136 means that i _{2 is} switched on, that is to say the string 32 is energized.

At S137 it is checked whether U _dif = L, cf. 11d, 11e and 11f: as long as U _dif = L, T _{d is} measured (with KOMM = H), and the values for P and I should consequently be changed in step S139. However, this change only takes place if U _difalt = L, ie if it has not been determined beforehand that the speed is too low when KOMM = L, and this is checked in step S138. (If the speed is too low, the values P and I may only be changed by the routine according to Fig. 17.)

In a step S21 0, a check is also carried out as a third condition as to whether REG = +1, and only if this is also the case does the program proceed to step S139, that is to say the "measurement phase", in which the values I and P during the duration of T _{d can be} changed.

If the result in steps S137, S138 and S210 is "yes", then in step S139 the factor I is increased by the value X, for example by the value 3, and the factor P is increased by Y, for example the value 1. I can be increased to a maximum of 255, P to a maximum of 15, whereby these numbers - as always - are only examples so that the matter does not become too dry. U _difalt remains on L in S 139. The UNLOAD register is set to L.

If in S137 U _{dif is} on H, _i.e. the measurement of T _{d is} complete, cf. 11, U _{difalt is set} to H and SENSAB to L in step S140, and the program goes directly to step S143, where the commutation counter KZ is incremented by the value 1. The same applies if U is _difalt = H in S138 and REG = -1 in S210.

S139 is followed by step S141, where it is checked whether I = 255, that is, his Has maximum value. This means the case in FIG. 11g, ie sensor break. Therefore if so, the register SENSAB is set to H in S142, which follows the motor switches to maximum speed. If I <255, then the program goes directly to S143.

After S142, the commutation counter KZ is also increased by the value 1 at S143 elevated.

It is then checked in a step S212 whether the value of the commutation counter reached KZ (in the microprocessor 20) is smaller than a threshold value S3 e.g. can have the value 260. If this is the case, the program goes to step S144. However, if KZ exceeds threshold S3, i.e. the engine turns extremely slow or stopped (rotor 27 is blocked), the program goes to step S214, where the currents in both lines 31 and 32 are switched off. It there follows a waiting time of S216 e.g. 3 seconds, i.e. the engine stays 3 Seconds without power, and the program then goes to step S162 in Fig. 20, where an alarm may be triggered. After that, the current in the motor is renewed switched on, i.e. a new start-up attempt follows automatically after approx. 3 Waiting seconds so that the engine cannot overheat, but immediately starts again when the blocking has been removed.

If the answer is yes in step S212, then in step S144 checked whether the signal KOMM has changed. Is it still the same? the program loops back to step S133. Did that Signal COMM changed, the program proceeds to the routine of FIG. 18.

Fig. 17 shows the continuation of Fig. 15 for the case that COMM = L. This routine is implemented in FIG. 12. With it, the measuring processes, ie the changes in I and P, are only carried out if the motor is too slow. 21 shows an example of the processes in this routine.

In step S147, the output 13 of the microprocessor 20 is set to H, that is to say DISCHARGE = H. FIG. 21 c shows that when DISCHARGE = H the charging of the capacitor C begins and the voltage U _C (FIG. 21b) consequently rises.

As FIG. 21 c shows, the DISCHARGE signal is only set to H at a time interval from the change in the signal KOMM (from H to L). The time interval corresponds to the duration of the calculation phase 128 (FIG. 21d), which is explained below with reference to FIGS. 19 and 20. This change in the DISCHARGE signal from L to H can only take place if KOMM has previously changed from H to L, ie this change is only part of the routine according to FIG. 17.
Step S148 corresponds to S133.
Step S149 corresponds to S134.
Step S150 corresponds to S135.
Step S151 corresponds to S136, with the difference that the current i _{1 is} switched on at S151. Reference is made to the corresponding description of these steps in FIG. 16.

S152 checks whether U _{dif is} high. This corresponds to FIGS. 11b, 11c and 11d, ie T _d is only measured from the moment U _dif becomes high. If this is the case, it is next checked in step S222 whether REG = -1, cf. Step S207, ie whether the speed is too low. If so, the integral factor I is reduced by the value X (for example 3) at S153, the proportional factor P is increased by the value Y (for example 1), and U _difalt is set to H, so that the step _follows at COMM = H S139 is not executed and DISCHARGE is set to L, ie the capacitor C is immediately discharged again when U _{C has reached} the value U ₅₈ , as shown in FIGS. 21 b and 21 c. This has the advantage that sufficient time is available for the discharge via transistor 65 (FIG. 1), the signal U _difalt subsequently being a substitute for the signal U _dif .

If U _dif = L, the program goes to step S224, and there it is checked whether U _difalt = H. If yes, the program goes to step S222, if not, to step S154, where the commutation counter KZ is incremented by the value 1. It is then checked in step S226 whether KZ is less than a threshold value S3 (eg 260), and if so, the program goes to step S155. If not, go to steps S228 and S230, and then to S162. Step S228 corresponds to S214 in FIG. 16, step S230 corresponds to S216 in FIG. 16. Reference is therefore made to the description there.

At S155 it is checked whether the signal KOMM has changed. Is it unchanged the program goes back to step S147. If KOMM has changed the program proceeds to the routine of FIG. 18.

Fig. 18 shows what happens next to Fig. 16 or Fig. 17. At S160, the test counter PZ (cf. S130) is increased to the value 1. This counter always counts to 15 and then goes back to zero.

At S161 it is therefore checked whether PZ = 15. If yes, routine 162 follows for ALARM (FIG. 20); if no, routine 163 (FIG. 19) follows for calculating the value PI. Both routines take place in the calculation phase 128 (FIG. 21d), that is to say immediately after commutation, which causes a - desired - small switch-on delay for the currents i ₁ and i ₂ . 12 and 13, these routines are always active in the rotary position ranges from 0 ° to approx. 10 ° and from 180 ° to approx. 190 °, where the motor 25 should be de-energized anyway. Both routines are advantageously of the same length in time, which can be achieved by the NOP instructions explained.

In FIG. 19 it is checked at S164 whether the register SENSAB = H, cf. S142 in Fig. 16. In this case, the value PI is set to zero in S165, which subsequently causes in Fig. 16 or 17 that the current is switched on already at KZ = 0, that is to say the motor with maximum output and consequently maximum speed running. A sensor tear (Fig. 1: break at 54 or 55) has the consequence that the motor behaves like a normal, uncontrolled motor.

If U _dif becomes H again at some point, SENSAB is reset to L (S140 in Fig. 16) and the speed is then controlled again.

If there is no sensor break, the previously determined factor P is multiplied by the sign signal REG at S166, and the formula is then used PI = I + 2P the value PI is determined, function see FIG. 21d.

At S167 it is checked whether the factor I is greater than a threshold value S1, e.g. greater than 240. If yes, the factor I is reset to the value R1 in S168, e.g. to 208. This prevents the alarm from being given at low speeds will, i.e. in this case the counter for 1 cannot reach the value 255 because by resetting his counter reading is kept artificially low. (In As I explained, when I = 255 is reached, PI is set to 0 and the motor runs at the same time maximum speed).

If the factor I is smaller than the threshold value S1, it is left unchanged, Step S169.

At S170 it is checked in an analogous manner whether the value PI is negative, and if yes, it is reset to zero at S171. Otherwise, it remains unchanged (S172).

S173 checks whether the lower speed limit (Fig. 2: n _min ) has been undershot and whether the factor I is greater than KZ _min (cf. S130 in Fig. 15).

If not, the program goes straight to step S131.

If the limit is exceeded, the controller switches to P control in step S174, ie the value PI is set to two KZ _min minus KZ. This prevents the speed n from falling below the lower limit value n _min (FIG. 2).

The value PI calculated with routine 163 is subsequently shown in FIG. 16 and / or Fig. 17 used, possibly during several consecutive cycles, such as already explained in Figs. 12 and 13, i.e. this is also possible after step S174 Program back to step S131 (Fig.15).

20 shows the alarm routine 162. In a step S240, the value for the alarm delay AVZ is reduced by the value 1, and it is then checked in S242 whether AVZ = 0. If yes, the program goes to step S175. There it is checked whether the value KZ is greater than the sum of KZ _min and a threshold value S2, which can have the value 47, for example. This sum can correspond to a speed of 1200 rpm, for example. If this sum is exceeded, the output 14 ("ALARM") of the microprocessor 20 is set to H (step S176) and an alarm is triggered. If the sum has not been exceeded, the program goes to step S244, where it is checked whether the output 4 (SEN) of the microprocessor 20 is high. If yes, a set alarm is not deleted, but is saved. If no, the ALARM signal is reset, that is to say cleared (step S 177).

If AVZ is greater than 0 in S242 (AVZ has a minimum value of 0), so goes the program returns from there directly to step S131 (FIG. 15), and this applies likewise with SEN = H, likewise after steps S176 or S177.

As already explained in detail in a preliminary remark relating to FIGS. 16 and 17, 16 and 17 are also used for time measurement, i.e. these loops are designed so that each pass through a loop does not matter in which way, requires the same time, so that by means of these loops a Time measurement is possible. The throughput times for the loops are after Fig. 16 and Fig. 17 are identical if possible.

This is achieved by inserting NOP instructions wherever else Loop pass would be too short. (NOP = No operation; a NOP command causes nothing, except a time delay in program execution. naturally you can use any other type of command instead of a NOP command that has no influence on the running of the motor.) The use of NOP commands is shown in Figures 22 and 23. Figure 22 is identical except for the NOP instructions 16 and FIG. 23 are identical to FIG. 17, except for the NOP instructions. The parts from FIGS. 16 and 17 are therefore not described again.

22 is between the YES output of step S133 and the node 249 a NOP instruction S250 inserted, which has the same duration as the step S134 so that the same for the YES and NO outputs of step S133 Duration of the run to node 252 results.

Between the NO output of step S138 and the NO output of In step S210 there is a NOP instruction S254, the duration of which is the period of Corresponds to S210.

Between the NO output of step S210 and the NO output of In step S139 there are several NOP instructions S256, the duration of which is that of Corresponds to step S139. (By going through several NOP instructions 256 there is a correspondingly longer time delay.)

Between the NO output of step S141 and the input of the step S143 is a NOP instruction S258, the duration of which is that of step S142 equivalent.

It can thus be seen that the loop according to FIG. 22 has the same time for each run required, regardless of which steps are carried out in the individual case.

Fig. 23 is identical to Fig. 17 except for the NOP instructions. Therefore, the Parts from Fig. 17 are not described again. 23 is between the YES output step S148 and node 260, a NOP command S262 is inserted, which has the same length of time as step S149, so that the output signals YES and NO of step S148 the same time period of the pass to node 264.

Is between the YES output of step S152 and node 266 a NOP instruction 268, the duration of which corresponds to step S224.

Between the NO output of step S222, that is to say node 270, and the output 272 of step S153, there are NOP instructions S274 whose combined time corresponds to the time of step S153.

It can thus be seen that the loop according to FIG. 23 does not matter for each run which way always takes the same time, regardless of which steps be run through in individual cases.

As already explained, the throughput time for the loop according to FIG. 22 is identical with the throughput time for the loop according to FIG. 23. This can possibly be achieved by this 22 between the YES output of step S144 and one or more NOP commands are switched on at the input of step S133 23 or alternatively in Fig. 23 between the YES output of step S155 and the input of step S147.

The throughput time for the loops according to FIGS. 22 and 23 should of course be as short as possible. This depends on the clock frequency of the microprocessor 20. The following times resulted for the 17103GS microprocessor with a clock frequency of 6 MHz: 22 or 23 (50 commands) 133 µs 19 time (38 commands) 102 µs 20 time (35 commands) 93μs

24 shows a graphical representation of the passage of several loops in the course of the commutation processes. 24a shows the commutation signal KOMM (analogous to FIG. 21a), and at time t ₂₇₀ it is assumed that in FIG. 18, step S160, the counter reading PZ = 13 has been reached. Therefore, the calculation of the value PI according to FIG. 19 follows in the calculation phase 70 (cf. FIG. 12).

23, and if, for example, the value 1 has been calculated for PI, the current i _{1 is switched} on at the time t ₂₇₂ after the first loop pass has elapsed. It is switched off after the end of the loop pass (n-x) at time t ₂₇₄ , that is to say before the commutation signal KOMM changes. This has already been described in detail and is therefore not repeated here. 24 has the value x in FIG. 24, ie the current i ₁ is switched off after the penultimate loop.

At time t ₂₇₆ , the commutation signal changes to H, and in FIG. 18 the count PZ = 14 is reached. In the calculation phase 76 (cf. FIG. 12), the value PI is therefore calculated again according to FIG. 19, and according to this value PI the current i _{2 is} switched on at time t ₂₇₈ , that is to say, for example, after the first loop run according to FIG. 22 , provided the value 1 for PI has resulted. The current i _{2 is switched off} after the end of the loop run (n-x) at the time t ₂₈₀ , that is to say before the change in the signal COMM. This has already been described in detail and is therefore not repeated here. (Steps S134 and S135 in Fig. 16; Steps 149 and S150 in Fig. 17). As an example, the quantity x has the value 1 here, ie the current i ₂ is switched off after the penultimate loop has ended.

At time t ₂₈₂ , the signal KOMM (FIG. 24a) changes to L, and in FIG. 18 the counter reading PZ = 15 is reached at the same time. This means that in the subsequent calculation phase 80 (cf. FIG. 12) the alarm signal according to FIG. 20 is calculated. The loops according to FIG. 23 are then run through again. In this case, the value PI is taken over unchanged from the calculation phase 76, as already described in FIG. 12.

The commutation counter KZ therefore counts the number of loops according to FIG. 22 or 23 that are run through and approximately determines the time interval between successive commutation times, e.g. between times t ₂₇₀ , t ₂₇₆ , t ₂₈₂ etc. Since each loop has one has a predetermined period of time, the commutation counter KZ measures a period of time.

The calculation phases 70, 76, 80 etc. have a predetermined time period, ie with increasing motor speed their percentage share in the time period between two commutation signals (eg between t ₂₇₀ and t ₂₇₆ in FIG. 24) increases, which is advantageous. The calculation phases result in a current gap, which is particularly advantageous in the case of two-pulse motors, especially at high speeds and consequently high amplitudes of the currents i ₁ and i ₂ . If, for example in FIG. 24c, the amplitude of the current i _{1 is} so high that it has not yet dropped to 0 at the time of commutation t ₂₇₆ , this is not a problem since this current i ₁ only reached the value 0 at the end of the calculation phase 76 must, because the current i _{2 can be} switched on at the earliest at this time. (The currents i ₁ and i ₂ should not flow at the same time, as this can lead to strong radio interference and motor noise and deteriorate the efficiency of the motor. This would also result in high braking torques.) The same applies to the current i ₂ , which only occurs within the Calculation phase 80 must have reached the value 0.

As already shown in a numerical example, the duration of the calculation phases can 70, 76, 80 etc. differ slightly, depending on whether a calculation of the PI value (FIG. 19) or an alarm calculation (FIG. 20) is carried out. The differences in the duration of the calculation phases are usually in the Order of magnitude of a few µs, so that it has no influence on the running of the motor to have. But you could also do the calculation phases using NOP commands make it the same length, if desired.

The throughput times through the loops according to FIGS. 22 and 23 should, however, should be as long as possible, since the loop passes in the commutation counter Concentration camp are summed up and consequently also smaller differences in the Sum up the sum and cause the engine to run rough can. For example, the time difference between a loop pass 22 and a loop pass of FIG. 23 three µs, and the loops if each run 50 times, there is a time difference of 50 x 3 µs = 150 µs, which is more than the duration of a full loop pass would correspond. Such mistakes must be avoided if a calm one Running the engine is desirable.

25 shows the circuit analogous to FIG. 1 when the motor is designed for maximum speed, that is to say without speed control. The input 6 of the microprocessor 20 is connected to the negative line 46 via a resistor 286. This corresponds to a constant value of U _dif = 0, that is to say the break in the supply line to sensor 26 at point 54 or 55 in FIG. 1. In this case, the motor runs uncontrolled at maximum speed, that is to say according to step S165 in FIG. 19 PI = 0 is set, and a motor current flows directly from the end of the respective calculation phase 70, 76, 80 etc. (FIGS. 12 and 24).

The other functions of the engine remain unchanged in FIG. 25 received, i.e. the motor can be switched on and off without power (step S132 in FIG. 15), the alarm function operates unchanged, as with FIG. 20 described, as well as the blocking protection (steps S214, S216 in Fig. 16; Steps S228, S230 in Fig. 17). By means of the inputs NG0 shown in FIG. 5, Different alarm speeds can be programmed in NG1. By means of the Input SEN (FIG. 5) can program the alarm storage according to FIG. 20 alarm delay and the ATS input. In this case So the microprocessor 20 takes over the commutation, the blocking protection and alarm monitoring while there is no speed control. The speed in this case, the motor is determined by the operating voltage and by designing the winding of the motor. It has been shown that this variant is sufficient in many cases and represents an inexpensive alternative, especially with regard to alarm monitoring and blocking protection, which are both taken over by the microprocessor, which also the Commutation of the motor controls.

The analog device for calculating the control deviation can also be replaced by a digitally working device according to the same principle, in which case, for example, a counter can be used as the storage element, which emits a signal U _dif when a certain temperature-dependent limit value is reached. The principle remains exactly the same. However, the analog measurement is currently preferred because it is extremely simple and does not require an analog-digital converter, for example for the temperature.

In the exemplary embodiment described above for a two-pole rotor 27 the rotary position values were given in mechanical degrees, e.g. 180 °. In the case of a rotor with more than one pole pair, these values must be followed electrical degrees are replaced, e.g. instead of 180 ° then 180 ° el. (electrical degrees), as is familiar to the specialist in electrical engineering.

Claims (19)

1. Method for monitoring a commutatorless direct-current motor, with the following features:

   a) when a predetermined phase winding of the motor is energised, the length of time (KZ) of the commutation phase roughly from the commutation at the beginning of this commutation phase to roughly to the commutation at the end of this commutation phase is detected continuously as a digital value;

   b) this length of time (KZ) is compared with a predetermined threshold value (S3);

   c) if this length of time (KZ) exceeds the threshold value (S3), an alarm signal (ALARM) is set (S176), possibly allowing for additional parameters.
2. Method according to claim 1, in which a programme loop with a predetermined length of time is run through a plurality of times in succession for roughly the length of time of a commutation phase and each loop pass is detected in a counter (KZ) in order to detect the length of time of this commutation phase continuously.
3. Method for influencing the rotational speed of a commutatorless direct-current motor, with the following features:

   a) when a predetermined phase winding of the motor is energised, the length of time (KZ) of the commutation phase roughly from the commutation at the beginning of this commutation phase to roughly to the commutation of the end of this commutation phase is detected continuously as a digital value;

   b) this length of time (KZ) is compared with a predetermined threshold value (S3);

   c) if this length of time (KZ) exceeds the threshold value (S3), the motor is de-energised (S228).
4. Method according to claim 3, in which the motor is de-energised in the step c) for a predetermined interval of time (S216; S230), and after this predetermined interval of time has elapsed, an attempt is made to turn on the motor anew.
5. Method according to claim 4, in which after the predetermined interval of time has elapsed, an alarm signal (ALARM) is set (S176).
6. Method according to one of claims 3 to 5, in which the length of time (KZ) of the commutation phases is detected continuously for more than one phase winding (31, 32) and in each case compared with the threshold value (S3).
7. Method according to one or more of the preceding claims, in which a programme loop with a predetermined length of time is run through a plurality of times during a commutation phase and each pass is counted in a loop counter (KZ).
8. Method according to claim 7, in which the loops of different commutation phases have different programme structures.
9. Method according to claim 7 or 8, in which the loop counter (KZ) controls at least one operation in the course of a commutation phase, e.g. turning on a current (S133), turning off a current (S134) and/or monitoring a minimum rotational speed (S212).
10. Method according to one or more of claims 7 to 9, in which the programme loop comprises a measuring algorithm (S137, 138, 139) for detecting a time difference (Td, Td') corresponding to a control deviation.
11. Method according to claim 10, in which the measuring algorithm comprises steps (S139; S153) for adapting a control parameter (I, P) to the detected time difference (Td, Td').
12. Method according to claim 10 or 11, in which the measuring algorithm (S139; S153) is present in the form of a branch in the programme loop which is only run through during the length of time of the time difference (Td, Td').
13. Method according to claim 12, in which the length of time for running through a programme loop is at least almost independent of whether the branch is run through or not.
14. Commutatorless direct-current motor with an arrangement for monitoring its rotational speed to see whether this rotational speed in operation falls below a lower limit value, with the following features:

    a) a device is provided which continuously detects the length of time (KZ) of a commutation phase roughly from the commutation at the beginning of this commutation phase to roughly to the commutation at the end of this commutation phase as a digital value;

    b) a device is provided for comparing this length of time (KZ) with a predetermined threshold value (S3);

    c) a device is provided which produces an alarm signal (ALARM) (S176) when this length of time (KZ) exceeds the threshold value (S3).
15. Motor according to claim 14, in which a programme loop with a predetermined length of time is run through a plurality of times in succession for roughly the length of time of a commutation phase and each pass is detected in a counter (KZ) in order to detect the length of time of a commutation phase.
16. Commutatorless direct-current motor according to claim 14 or 15, in which a counter (KZ) is provided for detecting the length of time of a commutation phase.
17. Commutatorless direct-current motor according to claim 16, in which the counter is part of a microprocessor or microcontroller (20) which serves for controlling the commutation of the motor.
18. Commutatorless direct-current motor according to claim 16 or 17, with a rotor the rotor magnet of which has trapezoidal magnetisation.
19. Use of a commutatorless direct-current motor according to one or more of claims 14 to 18 for driving a fan.

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